Copper possesses properties of excellent electrical and thermal conductivity and strong corrosion resistance; and is considered as electrical and thermal conductor of choice. Unfortunately, its supply on earth is relatively limited. In contrast, the supply of aluminum on earth is substantial greater as it is only preceded by oxygen and silicon. Aluminum possesses properties of small specific density, good electrical and thermal conductivity and mechanical ductility. Copper cladded aluminum composite (“CCAC”) possesses physical, chemical and mechanical properties of both copper and aluminum. CCAC is characterized by good electric and thermal conductivity, good corrosion resistance. It is lightweight and more affordable than copper.
Rapid development of networking technology, information technology, mobile and wireless communication, material science and technology, aeronautics and aerospace introduces great opportunities for application and development of metallic composites. CCAC has been used as a substitute for copper in the field of electrical and thermal conductivity. CCAC is also widely used in electronics, electrical power, metallurgy, machinery, energy, automobile, defense, aeronautics, aerospace and various industrial applications.
Nevertheless, its applications have been limited by its quality. Copper and aluminum can be easily oxidized. They have very different yield strength, density, coefficient of heat expansion. These differences have limited the quality of conventionally produced CCAC. Current CCAC products are produced by various conventional methods such as explosive binding, weld binding, roll binding, drawing binding, liquid-solid phase binding, liquid-liquid phase binding, etc. These methods, even under extreme processing conditions (such as large deformation rate of rolling, annealing at high temperature, or the like), do not produce a high quality CCAC that can act as a full and complete substitute for copper in its various electrical applications. These current CCAC products generally have restrictions as to their low binding strength due to less bimetallic diffusion; small depth of transitional binding; and poor physical uniformity and consistency of materials. Furthermore, these conventional methods provide low yield rate of production and are not capable of being a continuous manufacturing process.
If CCAC is to be used for electric power transmission and certain electrical applications, strong bimetallic interfacial bonding strength and copper layer uniformity and consistence are desired. It is also desired that such CCAC provides thermal stability, carries electrical current evenly, maintains long servicing life, and can be subjected to machining processing (such as punching, shearing, bending, distorting or the like) without affecting the quality and/or performance of CCAC.